Abstract: To carry out the basic national policy of arable land protection, we make out the most serious policy of arable land protection. But the effect of the policy is not ideal,and the goal of keeping the balance of the gross of arable land is not coming true. The article analyses the reason on gross unbalance of arable land from the economic angle and come to the conclusion that the main reason of that is being shorting of economic mechanism of interiorizing of exterior action, inspiriting and restricting to the local government, and of property rights and property ability of arable land, zero game to arable land protection between developed area and developing area. So that, some suggestion and advice were given.